Proposals for the Origin of the Grand Canyon

Although not addressing the Grand Canyon, several early geologists suggested a mechanism for carving a canyon: breaching a large lake’s boundary. If a large lake spills over the lowest point on its boundary, a notch will be cut that will allow more water to flow through the notch faster, eroding the notch even deeper. If the lake is large, the initial loss of water will not lower the lake’s level too much, but the notch will deepen rapidly. The lake will discharge catastrophically through a deep slit—quickly forming a canyon.24 The process is similar to the collapse of a dam. Modern examples of breached dams include the 1889 Johnstown Flood in Pennsylvania, which killed at least 2,200 people, and the 1976 Teton Flood in Idaho, which killed fourteen people and left 25,000 homeless.

In 1861, John Strong Newberry proposed an explanation for the small canyons and basins along the Colorado River far south and west of the Grand Canyon. He wrote:

Doubtless in earlier times [the Colorado River] filled these basins to the brim, thus irrigating and enriching all its course. In the lapse of ages, however, its accumulated waters, pouring over the lowest points in the barriers which opposed their progress towards the sea, have cut them down from summit to base forming that remarkable series of deep and narrow caÅons through which its turbid waters now flow, with rapid and almost unobstructed current, from source to mouth.25

Newberry also wrote that the Grand Canyon, which he called The Great CaÅon, was “wholly due to the action of water. Probably nowhere in the world has the action of this agent [water] produced results so surprising, both as regards their magnitude and their peculiar character.”26

In 1923, another geologist, J Harlen Bretz, proposed that a network of canyons had been carved in Washington State by the breaching of a natural dam. He said that an ice dam impounded a lake in Montana and northern Idaho. The lake, which Bretz called Lake Missoula, was about half the size of Lake Michigan. When Lake Missoula breached, canyons and other terrain, called the Channeled Scablands, were carved. Because Bretz’s explanation was too catastrophic, geologists rejected his views for more than 40 years. Today, his views are widely accepted.27 (Invoking catastrophes violated a “sacred” rule in geology; i.e., explanations should involve only processes that we see today. Evolutionary geologists believe that eons of time were available. Unfortunately, this assumption, called uniformitarianism, still underlies much of geology.)

The following are the best-known published proposals for the origin of the Grand Canyon. Most assume that the Colorado River carved the canyon. All theories try to explain how the Colorado River traversed the high Kaibab Plateau. Some proposals contain few details, because relatively little was known about the canyon and surrounding region when those proposals were published.

John Wesley Powell (1869). Over geologic time, thousands of feet of limestone, shale, and sandstone layers were deposited. The earth, cooling from its earlier molten state, was contracting and shriveling, like a dried-up, wrinkled apple. As the Colorado River flowed along its present course 65,000,000 years ago, surface rocks began folding, uplifting, and tilting. The Colorado Plateau rose so slowly that the river was never blocked. As it did, the river cut through the rising land, leaving the Grand Canyon.28

In fairness to Powell, the mechanism he proposed for the Grand Canyon’s origin was based on terrain he saw two months before he entered the Grand Canyon and 400 miles to the northeast. When he and his group reached the Grand Canyon, they were in a race for their lives, rations were running low, the rapids were treacherous, morale was low, escape routes were limited, and constraining canyon walls permitted little exploration. Two weeks later, three team members were killed as they tried to leave that hostile environment.

Grove Karl Gilbert (1875). Faults developed in the Colorado Plateau as it rose over long periods of time. These cracks allowed the Colorado River to flow through the Kaibab Plateau and carve the Grand Canyon.29

Samuel Franklin Emmons (1897). To form the Grand Canyon, either the Colorado River cut down through the land below, or the land below rose up and was cut by the river. Powell maintained the latter, but he misread specific geologic features. [Emmons provided valid but complex details.30] Therefore, the river settled down through the land and carved the Grand Canyon by superposition.

Eliot Blackwelder (1934). Up until 1.8 million years ago, the Colorado River did not exist. Then, as the Rocky Mountains rose their last mile or so, they intercepted more moisture from the westerly winds. Rivers flowing down the western slopes of the Rockies became longer and more powerful. River drainage into basins west of the Rockies increased, while the cold, ice age climate reduced evaporation. Therefore, western lakes grew and sometimes breached their banks, carving canyons down to the next lower lake. Eventually, the Grand Canyon was carved and the Colorado River flowed as it does today.31

Edwin D. McKee (1964). The early Colorado River flowed into the Gulf of Mexico along a path that began east of the Kaibab Plateau, then continued along the valley of the Little Colorado River, and finally flowed into the Rio Grande. During the next 8,000,000 years, the Colorado Plateau rose and some streams flowed westward off the Colorado Plateau. One stream eroded headward (upstream) 300 miles northward from the Gulf of California, then 130 miles eastward through the Kaibab Plateau. The stream eventually captured the waters of the Colorado River, which then changed course and began flowing west, where it eroded the Grand Canyon.32

Charles B. Hunt (1976). The Grand Canyon was carved in segments. First, the eastern part was partially carved both by superposition and by the land rising as the river cut down through it. The river ponded in a large basin north of Kingman, Arizona. Later, that lake tunneled northward through caverns and limestone deposits, exiting as a spring feeding another lake just beyond today’s western end of the Grand Canyon. This is how and where the Hualapai Limestone accumulated. When the flow from east of today’s Grand Canyon increased, lakes overflowed, cutting the western Grand Canyon. Over the next few million years, the Colorado River cut the canyon to its present depth.33

Ivo Lucchitta (1988). The early Colorado River flowed southwest across a flatter Kaibab Plateau, cutting down through it by superposition. West of that plateau, the river flowed to the northwest. Faulting and volcanism have since erased that path.

About 5 million years ago, a stream began to flow south into the newly opened Gulf of California. That stream eroded headward along what is now the Colorado River’s path after it leaves the Grand Canyon. Further headward erosion to the east allowed the stream to intersect and capture, west of the Kaibab Plateau, the Colorado River, which then carved the Grand Canyon.34

Norman Meek and John Douglass (2000). About 6,000,000 years ago, the Colorado River drained into Hopi Lake. Eventually, the lake breached, spilling over the Kaibab Plateau to the west. The released water filled other basins downstream, forming lakes that breached successively. The region west of today’s Grand Canyon may have subsided by almost one mile, and the Colorado Plateau may have tipped to the southwest, giving the waters from the upper Colorado River enough energy to carve the Grand Canyon.38